Methocarbamol

Methocarbamol tablets USP a carbamate derivative of guaifenesin, is a central nervous system (CNS) depressant with sedative and musculoskeletal relaxant properties.

The chemical name of methocarbamol is 3-(2-methoxyphenoxy)-1,2-propanediol 1-carbamate and has the empirical formula C₁₁H₁₅NO₅. Its molecular weight is 241.24. The structural formula is shown below.

Methocarbamol is a white powder, sparingly soluble in water and chloroform, soluble in alcohol (only with heating) and propylene glycol, and insoluble in benzene and n-hexane.

Methocarbamol tablets USP are available as 500 mg and 750 mg tablets for oral administration. Methocarbamol tablets USP 500 mg and 750 mg contain the following inactive ingredients: sodium lauryl sulfate, sodium starch glycolate, povidone K 90, polyethylene glycol, magnesium stearate, colloidal silicon dioxide, low substituted hydroxy propyl cellulose and stearic acid.

The mechanism of action of methocarbamol in humans has not been established, but may be due to general central nervous system (CNS) depression. It has no direct action on the contractile mechanism of striated muscle, the motor end plate or the nerve fiber.

Methocarbamol tablets USP are indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions. The mode of action of methocarbamol has not been clearly identified, but may be related to its sedative properties. Methocarbamol does not directly relax tense skeletal muscles in man.

Methocarbamol tablets USP are contraindicated in patients hypersensitive to methocarbamol or to any of the tablet components.

Since methocarbamol may possess a general CNS depressant effect, patients receiving methocarbamol tablets USP should be cautioned about combined effects with alcohol and other CNS depressants.

Safe use of methocarbamol tablets USP has not been established with regard to possible adverse effects upon fetal development. There have been reports of fetal and congenital abnormalities following in utero exposure to methocarbamol. Therefore, methocarbamol tablets USP should not be used in women who are or may become pregnant and particularly during early pregnancy unless in the judgment of the physician the potential benefits outweigh the possible hazards (see PRECAUTIONS, Pregnancy)

Adverse reactions reported coincident with the administration of methocarbamol include:

Body as a whole: Anaphylactic reaction, angioneurotic edema, fever, headache

Cardiovascular system: Bradycardia, flushing, hypotension, syncope, thrombophlebitis

Digestive system: Dyspepsia, jaundice (including cholestatic jaundice), nausea and vomiting

Hemic and lymphatic system: Leukopenia

Immune system: Hypersensitivity reactions

Nervous system: Amnesia, confusion, diplopia, dizziness or lightheadedness, drowsiness, insomnia, mild muscular incoordination, nystagmus, sedation, seizures (including grand mal), vertigo

Skin and special senses: Blurred vision, conjunctivitis, nasal congestion, metallic taste, pruritus, rash, urticaria

Limited information is available on the acute toxicity of methocarbamol. Overdose of methocarbamol is frequently in conjunction with alcohol or other CNS depressants and includes the following symptoms: nausea, drowsiness, blurred vision, hypotension, seizures, and coma.

In post-marketing experience, deaths have been reported with an overdose of methocarbamol alone or in the presence of other CNS depressants, alcohol or psychotropic drugs.

Methocarbamol Tablets USP 500 mg – Adults:

Initial dosage: 3 tablets q.i.d.

Maintenance dosage: 2 tablets q.i.d.

Methocarbamol Tablets USP 750 mg – Adults:

Initial dosage: 2 tablets q.i.d.

Maintenance dosage: 1 tablet q.4h. or 2 tablets t.i.d.

Six grams a day are recommended for the first 48 to 72 hours of treatment. (For severe conditions 8 grams a day may be administered). Thereafter, the dosage can usually be reduced to approximately 4 grams a day.

Methocarbamol tablets USP 500 mg are white to off white, capsule shaped, tablets debossed with ‘H’ on scored side and ‘114’ on unscored side . They are supplied as follows:

Bottles of 30 NDC 65977-5033-0

Bottles of 60 NDC 65977-5033-1

Bottles of 100 NDC 65977-5033-2

Bottles of 500 NDC 65977-5033-3

Bottles of 1000 NDC 65977-5033-4

Methocarbamol tablets USP 750 mg are white to off white, capsule shaped, tablets debossed with ‘H’ on one side and ‘115’ on other side . They are supplied as follows:

Bottles of 30 NDC 65977-5034-0

Bottles of 60 NDC 65977-5034-1

Bottles of 100 NDC 65977-5034-2

Bottles of 500 NDC 65977-5034-3

Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature].

Dispense in tight container.

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Methocarbamol tablets, USP 500 mg 30 tablets

Methocarbamol tablets, USP 500 mg 60 tablets

Methocarbamol tablets, USP 500 mg 100 tablets

Methocarbamol tablets, USP 500 mg 500 tablets

Methocarbamol tablets, USP 500 mg 1000 tablets

Methocarbamol tablets, USP 750 mg 30 tablets

Methocarbamol tablets, USP 750 mg 60 tablets

Methocarbamol tablets, USP 750 mg 100 tablets

Methocarbamol tablets, USP 750 mg 500 tablets